Objective:To evaluate the cytotoxicity and hepatoprotective potentials of extracts,fractions or isolated compound from the leaves of Feronia limonia(F.limonia).Methods:Qualitative phytochemical analysis of extracts,fr...Objective:To evaluate the cytotoxicity and hepatoprotective potentials of extracts,fractions or isolated compound from the leaves of Feronia limonia(F.limonia).Methods:Qualitative phytochemical analysis of extracts,fractions or compound was performed by means of thin layer chromatography and spectroscopic assays.The%purity of compound was measured by analytical HPLC.Extracts,fractions or compound have been individually evaluated for their cytotoxicity effects(10,20,100,250,500,750 and 1 000 μg/mL).Based on the inhibitory concentration(IC_(50)) obtained from the cell viability assay,graded concentrations of extracts,fractions or isolated compound were assessed(10,20,50,100,200 μg/mL) for its hepatoprotective potential against CCl_4-induced hepatotoxicity by monitoring activity levels of serum glutamatic pyruvatic transaminase(SGPT) and serum glutamic oxaloacetic transaminase(SGOT).Results:Results indicated that the methanol extract of F.limonia was non-toxic and hepatoprotective in nature as compared with the petroleum ether extract.The acetone fraction of methanolic extract also showed similar properties but the subsequent two fractions were cytotoxic.However,the pure compound isolated from the penultimate fraction of methanolic extract was non-toxic and hepatoprotective in nature.Biochemical investigations(SCOT,SCPT) further corroborated these cytological observations.Conclusions:It can be concluded from this study that F.limonia methanol extract,some fractions and pure isolated compound herein exhibit hepatoprotective activity.However,cytotoxicity recorded in the penultimate fraction and investigation of structural details of pure compound warrants further study.展开更多
The distribution of temperature and then the distribution of residual stress and distortion in the stiffened aluminum alloy Al6061-T6 plates under the metal inert gas(MIG)welding process were investigated by three dim...The distribution of temperature and then the distribution of residual stress and distortion in the stiffened aluminum alloy Al6061-T6 plates under the metal inert gas(MIG)welding process were investigated by three dimensional thermo-mechanical coupled finite element model using Ansys software.The properties of materials were considered temperature-dependent and the filler metal was added to the workpiece by the element birth and death technique.In three modes of current,two different speeds and two various sequences,the distribution of residual stress and distortion were calculated and analyzed.The results showed that increase in welding speed decreased the vertical deflection in the plate,transverse shrinkage and angular distortion of plate and the lateral deflection of stiffener,but increased the maximum longitudinal tensile stress in the plate and stiffener.Furthermore,increase in current increased the residual stress and deformation in the plate and stiffener,and the change in the welding sequence changed the distribution of the distortion in the plate and the stiffener without significant change in the distribution of the longitudinal residual stress.展开更多
Intercropping, as an overyielding system, can decrease soil erosion on sloping land through the presence of dense canopy covers. However, the structure mechanism in canopy is still unclear. We conducted a two-year fie...Intercropping, as an overyielding system, can decrease soil erosion on sloping land through the presence of dense canopy covers. However, the structure mechanism in canopy is still unclear. We conducted a two-year field experiment on runoff plots, exploring whether the interaction between vegetation layers reduce soil erosion in maize and potato intercropping systems. The maize, potato, and weed layers in the intercropping system were removed by a single layer, two layers and three layers, respectively(total of 8 treatments including all layers removed as the control). Then, throughfall, runoff and sediment were measured at the plot and row scale on a weekly basis. Based on the difference between each treatment and the control, we calculated and found a relative reduction of runoff and sediment by any combination of the two vegetation layers greater than the sum of each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 15.65% and 46.73%, respectively. Sediment loss decreased by 33.96% and 42.77%, respectively. Moreover, runoffand sediment reduced by the combination of all vegetation layers(no layers removed) was also larger than the sum of that by each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 7.32% and 3.48%, respectively. So, there were synergistic effects among multi-level(two or three layers) vegetation layers in terms of decreasing soil erosion on sloping land. Maize redistributes more throughfall at the maize intra-specific row and the maize and potato inter-specific, which is favorable for the synergistic effect of reducing soil erosion. This finding shows an important mechanism of maize and potato intercropping for soil and water conservation, and may promote the application of diverse cropping systems for sustainable agriculture in mountainous areas.展开更多
Eringen's nonlocal elasticity theory is extensively employed for the analysis of nanostructures because it is able to capture nanoscale effects.Previous studies have revealed that using the differential form of th...Eringen's nonlocal elasticity theory is extensively employed for the analysis of nanostructures because it is able to capture nanoscale effects.Previous studies have revealed that using the differential form of the strain-driven version of this theory leads to paradoxical results in some cases,such as bending analysis of cantilevers,and recourse must be made to the integral version.In this article,a novel numerical approach is developed for the bending analysis of Euler-Bernoulli nanobeams in the context of strain-and stress-driven integral nonlocal models.This numerical approach is proposed for the direct solution to bypass the difficulties related to converting the integral governing equation into a differential equation.First,the governing equation is derived based on both strain-driven and stress-driven nonlocal models by means of the minimum total potential energy.Also,in each case,the governing equation is obtained in both strong and weak forms.To solve numerically the derived equations,matrix differential and integral operators are constructed based upon the finite difference technique and trapezoidal integration rule.It is shown that the proposed numerical approach can be efficiently applied to the strain-driven nonlocal model with the aim of resolving the mentioned paradoxes.Also,it is able to solve the problem based on the strain-driven model without inconsistencies of the application of this model that are reported in the literature.展开更多
Rapid and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and ultra performance liquid chromatography (RP-UPLC) method with UV detection has been developed and validated for quantification of...Rapid and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and ultra performance liquid chromatography (RP-UPLC) method with UV detection has been developed and validated for quantification of parathyroid hormone (PTH) in presence of meta-cresol as a stabilizer in a pharmaceutical formulation.Chromatography was performed with mobile phase containing 0.1% Trifluoroacetic acid (TFA) in MilliQ water and 0.1% TFA in acetonitrile with gradient program and flow rate at 0.3 mL/min for HPLC and 0.4 mL/min for UPLC.Quantification was accomplished with internal reference standard (qualified against innovator product and National Institute for Biological Standards and Control (NIBSC) standard).The methods were validated for linearity (correlation coefficient 0.99),range,accuracy,precision and robustness.Robustness was confirmed by considering three factors;mobile phase composition,column temperature and flow rate/age of mobile phase.Intermediate precision was confirmed on different equipments,different columns and on different days.The relative standard deviation (RSD) (<2% for RP-HPLC and <1% for UPLC,n=30) indicated a good precision.Retention time was found about 17 min and 2 min by HPLC and UPLC methods,respectively.Both methods are simple,highly sensitive,precise and accurate and have the potential of being useful for routine quality control.展开更多
This study focuses on the development of a farm of tidal turbines in the Khuran Channel.The important factors include the location of turbines and their hydrodynamic effects on the environment.A three-dimensional circ...This study focuses on the development of a farm of tidal turbines in the Khuran Channel.The important factors include the location of turbines and their hydrodynamic effects on the environment.A three-dimensional circulation model for the Persian Gulf is employed for the comprehensive evaluation of the tidal energy potential throughout the study area.The model is validated by using in situ observations of water level and current data.The appropriate potential points for extracting the tidal energy were identified in the Persian Gulf using the model results.The Khuran Channel,located in the north of Qeshm Island,was found to be the best place to extract tidal energy inside the Persian Gulf.By adding the term of momentum losses to the governing equations,the feedback of extracting energy on the hydrodynamic around Qeshm Island was studied.The simulation results show that the average daily power production of a tidal farm with 99 turbines for one month is approximately 1.3 MW.This tidal farm also has a significant impact on the water level inside the Khuran Channel,especially near the tidal farm where these fluctuations exceed 4 cm.The change in the current speed caused by wake reaches 0.4 m/s.Wake effects were active up to 7 km downstream of the turbines.The current velocity was also estimated to be 1.6 m/s and 2.1 m/s during the spring and ebb tides within the channel,respectively.展开更多
The size-dependent nonlinear buckling and postbuckling characteristics of circular cylindrical nanoshells subjected to the axial compressive load are investigated with an analytical approach. The surface energy effect...The size-dependent nonlinear buckling and postbuckling characteristics of circular cylindrical nanoshells subjected to the axial compressive load are investigated with an analytical approach. The surface energy effects are taken into account according to the surface elasticity theory of Gurtin and Murdoch. The developed geometrically nonlinear shell model is based on the classical Donnell shell theory and the von Karman＇s hypothesis. With the numerical results, the effect of the surface stress on the nonlinear buckling and postbuckling behaviors of nanoshells made of Si and Al is studied. Moreover, the influence of the surface residual tension and the radius-to-thickness ratio is illustrated. The results indicate that the surface stress has an important effect on prebuckling and postbuekling characteristics of nanoshells with small sizes.展开更多
Risk assessment and uncertainty approximation are two major and important parameters that need to be adopted for the development of pharmaceutical process to ensure reliable results.Additionally,there is a need to swi...Risk assessment and uncertainty approximation are two major and important parameters that need to be adopted for the development of pharmaceutical process to ensure reliable results.Additionally,there is a need to switch from the traditional method validation checklist to provide a high level of assurance of method reliability to measure quality attribute of a drug product.In the present work,evaluation of risk profile,combined standard uncertainty and expanded uncertainty in the analysis of acyclovir were studied.Uncertainty was calculated using cause-effect approach,and to make it more accurately applicable a method was validated in our laboratory as per the ICH guidelines.While assessing the results of validation,the calibration model was justified by the lack of fit and Levene＇s test.Risk profile represents the future applications of this method.In uncertainty the major contribution is due to sample concentration and mass.This work demonstrates the application of theoretical concepts of calibration model tests,relative bias,risk profile and uncertainty in routine methods used for analysis in pharmaceutical field.展开更多
This study investigated the effect of Zn foil layers on the microstructure and corrosion characteristics of friction stir welded aluminum alloy 5754.Samples of various joints were prepared by applying different rotati...This study investigated the effect of Zn foil layers on the microstructure and corrosion characteristics of friction stir welded aluminum alloy 5754.Samples of various joints were prepared by applying different rotational and welding speeds,and their microstructures were evaluated via a metallographic technique and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy elemental analysis.The anticorrosion behavior of joints in the absence and presence of a Zn interlayer was studied by cyclic potentiodynamic polarization test in 3.5 wt% Na Cl aqueous solution,and sound welds were obtained in the presence of the Zn interlayer foil.The results revealed that the joint made at a rotational speed of 800 r/min and traveling speed of 15 mm/min achieved a chemical composition identical to that of aluminum alloy 7 xxx series,and as such,it showed the best resistance to corrosion.展开更多
Objective:To assess the protective effects of lycopene on electrocardiographic,hemodynamic, biochemical and apoptotic changes in isoproterenol induced myocardial infarction.Methods: Myocardial infarction was induced i...Objective:To assess the protective effects of lycopene on electrocardiographic,hemodynamic, biochemical and apoptotic changes in isoproterenol induced myocardial infarction.Methods: Myocardial infarction was induced in rats by subcutaneous injection of isoproterenol(200 mg/kg) for two consecutive days at an interval of 24 h.Rats were treated with lycopene(10 mg/kg/day, p.o.) for a period of 30 days and isoproterenol(ISO) was injected on the 29th and 30th day.At the end of experiment i.e.on the 31st day electrocardiographic,hemodynamic,biochemical and apoptotic changes were monitored from control and experimental groups.Results:ISO injected ruts showed a significant alteration in electrocardiograph pattern and hemodynamic changes(i.e. systolic,diastolic and mean arterial pressure).It also showed significant increase in C-reactive protein,myeloperoxidase,nitrite levels and Caspase-3 protease activity.In addition,it also exhibited alteration in the levels of electrolytes(Na^+,K^+ and Ca^(2+),vitamin E,uric acid and serum protein.Cel electrophoresis of ISO injected rats showed increase in DNA fragmentation.Triphenyl tetrazolium chloride staining of the heart section shows increase area of infarction in ISO injected rats.Pre-co-treatment with lycopene significantly prevented the ISO induced ullerution in ECC, haemodynamic,biochemical and apoptotic changes.Conclusions:The present result shows that treatment of lycopene in ISO injected rats significantly attenuates induced myocardial infarction.展开更多
Dry powder inhaler Liposomes were prepared to investigate the effectiveness of pulmonary delivery of Colchicine and Budesonide for Idiopathic Pulmonary fibrosis. Budesonide(BUD) and Colchicine(COL) liposomes were prep...Dry powder inhaler Liposomes were prepared to investigate the effectiveness of pulmonary delivery of Colchicine and Budesonide for Idiopathic Pulmonary fibrosis. Budesonide(BUD) and Colchicine(COL) liposomes were prepared by thin layer film hydration method(TFH) using 1,2-Dipalmitoyl-sn-glycero-3-phosphoglycerol sodium(DPPG), Hydrogenated Soyaphosphotidylcholine(HSPC), Soyaphosphatidylcholine(SPC), cholesterol(CHOL) and drug in different weight ratios. The optimum lipid composition for BUD(74.22 ± 0.97%) was DPPG:HSPC: CHOL(4:5:1) and for COL(50.94 ± 2.04%) was DPPG: SPC: CHOL(3:6:1). These compositions retained drug for a longer period of time so selected for further study. Liposomes were found to be spherical in shape with mean size below 100 nm. Liposomes lyophilized using Mannitol as carrier and cryoprotectant showed high entrapment efficiency(97.89-98.6%). The powder was dispersed through an Andersen cascade impactor to evaluate the performance of the aerosolized powder. It was found that prepared liposomal dry powder inhaler(DPIs) sustained the drug release up to 24 hours. Optimized Budesonide DPI Formulation B2(86.53 ± 1.9%), Colchicine DPI Formulation C2(90.54 ± 2.3 %) and BUD and COL DPI Combination M2(89.91 ± 1.8%, 91.23 ± 1.9%). Histopathological results, measurements of lung hydroxyproline content, Myeloperoxidase activity indicated that liposomal drypowder inhaler administration attenuates lung fibrosis induced by bleomycin. Long term stability studies indicated that lyophilised BUD and COL liposomes were stable for 6 months at(25 °C± 2 °C, 60% ± 5% RH) and refrigerated conditions(2-8 °C). These results supported that combination of budesonide and colchicine liposomal dry powder inhaler pulmonary drug delivery for treatment of idiopathic Pulmonary Fibrosis exhibits prolonged drug retention at targeted site and reduces the systemic exposure.展开更多
Objective:To investigate the protective effects of hydroalcoholic and its fractions from roots of Hemidesmus indicus on arthritis in in vitro models of rodents.Methods:Preliminary phytochemical analysis and thin-layer...Objective:To investigate the protective effects of hydroalcoholic and its fractions from roots of Hemidesmus indicus on arthritis in in vitro models of rodents.Methods:Preliminary phytochemical analysis and thin-layer chromoatography were performed to analyze constituents of hydroalcoholic extract and its three fraction namely ethyl acetate fraction,chloroform fraction and residual fraction of mot of Hemidesmus indicus.Arthritis rats models were established by Complete Freund’s Adjuvant.The parameters including paw edema,body weight,arthritic index,erythrocyte sedimentation rate,serum rheumatoid factor,serum C-reactive protein,serum nitrite level,and histopathology of synovial joints were observed.Methotrexate was taken as positive control.Results:Rats treated with hydroalcoholic extract(450 mg/kg,p.o.),ethyl acetate (75 mg/kg,p.o.),chloroform(60 mg/kg,p.o) and residual fractions(270 mg/kg,p.o.),showed significant decrease in physical and biochemical parameters compared with arthritic model rats. Hydroalcoholic extract and its ethyl acetate fraction of Hemidesmus indicus showed significantly higher anti-arthritic activity than chloroform and residual fraction.Histopathological analysis demonstrated that both of hydroalcoholic extract and its ethyl acetate fraction had comparable anti-arthritic activity with methotrexates.Conclusions:The present study suggests that Hemidesmus indicus has protective activity against arthritis and the activity might be attributed to presence of terpenoid in hydroalcoholic extract,as well as in ethyl acetate fraction.展开更多
A novel size-dependent model is developed herein to study the bending behavior of beam-type micro/nano-structures considering combined effects of nonlocality and micro-rotational degrees of freedom. To accomplish this...A novel size-dependent model is developed herein to study the bending behavior of beam-type micro/nano-structures considering combined effects of nonlocality and micro-rotational degrees of freedom. To accomplish this aim, the micropolar theory is combined with the nonlocal elasticity. To consider the nonlocality, both integral (original) and differential formulations of Eringen’s nonlocal theory are considered. The beams are considered to be Timoshenko-type, and the governing equations are derived in the variational form through Hamilton’s principle. The relations are written in an appropriate matrix-vector representation that can be readily utilized in numerical approaches. A finite element (FE) approach is also proposed for the solution procedure. Parametric studies are conducted to show the simultaneous nonlocal and micropolar effects on the bending response of small-scale beams under different boundary conditions.展开更多
An analytical approach is proposed to study the postbuckling of circular cylindrical shells subject to axial compression and lateral pressure made of functionally graded graphene platelet-reinforced polymer composite ...An analytical approach is proposed to study the postbuckling of circular cylindrical shells subject to axial compression and lateral pressure made of functionally graded graphene platelet-reinforced polymer composite (FG-GPL-RPC). The governing equations are obtained in the context of the classical Donnell shell theory by the von K′arm′an nonlinear relations. Then, based on the Ritz energy method, an analytical solution approach is used to trace the nonlinear postbuckling path of the shell. The effects of several parameters such as the weight fraction of the graphene platelet (GPL), the geometrical properties, and distribution patterns of the GPL on the postbuckling characteristics of the FG-GPL-RPC shell are analyzed.展开更多
This paper describes a sensitive spectrophotometric method developed for determination of Ketoconazole (KC) in tablets based on amplification reactions. Ketoconazole was oxidized with periodate, resulting in formation...This paper describes a sensitive spectrophotometric method developed for determination of Ketoconazole (KC) in tablets based on amplification reactions. Ketoconazole was oxidized with periodate, resulting in formation of KC2t and iodate ions. After masking the excess periodate with molybdate, the iodate was treated with iodide to release iodine. The liberated iodine was transformed to ICl2 species and extracted as ion-pair with rhodamine 6G into toluene for spectrophotometric measurement at 535 nm. A linear calibration graph was obtained between 0.2136 mg/mL and 1.7088 mg/mL of Ketoconazole with a molar absorptivity of 5 105 mol L 1 cm 1. The procedure was successfully applied for the determination of ketoconazole in tablet formulation.展开更多
The(1+2)-dimensional chiral nonlinear Schr?dinger equation(2D-CNLSE)as a nonlinear evolution equation is considered and studied in a detailed manner.To this end,a complex transform is firstly adopted to arrive at the ...The(1+2)-dimensional chiral nonlinear Schr?dinger equation(2D-CNLSE)as a nonlinear evolution equation is considered and studied in a detailed manner.To this end,a complex transform is firstly adopted to arrive at the real and imaginary parts of the model,and then,the modified Jacobi elliptic expansion method is formally utilized to derive soliton and other solutions of the 2D-CNLSE.The exact solutions presented in this paper can be classified as topological and nontopological solitons as well as Jacobi elliptic function solutions.展开更多
In this paper, thermoluminescence （TL） properties of rare earth Tb^3＋-doped α-Sr2P2O7 were examined after β-irradiation and photoluminescence （PL） properties of samples were examined for proper excitation. All ...In this paper, thermoluminescence （TL） properties of rare earth Tb^3＋-doped α-Sr2P2O7 were examined after β-irradiation and photoluminescence （PL） properties of samples were examined for proper excitation. All the samples were synthesized by high-temperature combustion method. The X-ray diffraction （XRD） and Fourier transform infrared （FTIR） spectroscopy characterization confirms the formation of pure α-phase with crystallized in orthorhombic structure of samples. The PL emission spectra of all samples exhibit characteristic green emission peaks of Tb^3＋ where the peak at 545 nm has the highest emission intensity for Tb^3＋ con- centration of 5.0 mol%. The TL glow curves of β-irradiated Tb^3＋-doped α-Sr2P2O7 phosphors were recorded at different heating rates of 2, 4, and 6 K.s^-1. TL curves of all sample exhibit combination of two peaks： peak at 420 K shifts toward higher 525 K remains unaffected temperature, while peak at with the increase in Tb^3＋ concentration as well as fading effect. The activation energy and kinetic parameters of the samples were evaluated using thermoluminescence peak shape method.展开更多
To study controlled evolution of nonautonomous matter-wave breathers and rogue waves in spinor Bose–Einstein condensates with spatiotemporal modulation,we focus on a system of three coupled Gross–Pitaevskii equation...To study controlled evolution of nonautonomous matter-wave breathers and rogue waves in spinor Bose–Einstein condensates with spatiotemporal modulation,we focus on a system of three coupled Gross–Pitaevskii equations with spacetime-dependent external potentials and temporally modulated gain-loss distributions.With different external potentials and gain-loss distributions,various solutions for controlled nonautonomous matterwave breathers and rogue waves are derived by the Darboux transformation method,such as breathers and rogue waves on arched and constant backgrounds which have the periodic and parabolic trajectories.Effects of the gain-loss distribution and linear potential on the breathers and rogue waves are studied.Nonautonomous two-breathers on the arched and constant backgrounds are also derived.展开更多
In this study,we analyze three portfolio selection strategies for loss-averse investors:semi-variance,conditional value-at-risk,and a combination of both risk measures.Moreover,we propose a novel version of the non-do...In this study,we analyze three portfolio selection strategies for loss-averse investors:semi-variance,conditional value-at-risk,and a combination of both risk measures.Moreover,we propose a novel version of the non-dominated sorting genetic algorithm II and of the strength Pareto evolutionary algorithm 2 to tackle this optimization problem.The effectiveness of these algorithms is compared with two alternatives from the literature from five publicly available datasets.The computational results indicate that the proposed algorithms in this study outperform the others for all the examined performance metrics.Moreover,they are able to approximate the Pareto front even in cases in which all the other approaches fail.展开更多
文摘Objective:To evaluate the cytotoxicity and hepatoprotective potentials of extracts,fractions or isolated compound from the leaves of Feronia limonia(F.limonia).Methods:Qualitative phytochemical analysis of extracts,fractions or compound was performed by means of thin layer chromatography and spectroscopic assays.The%purity of compound was measured by analytical HPLC.Extracts,fractions or compound have been individually evaluated for their cytotoxicity effects(10,20,100,250,500,750 and 1 000 μg/mL).Based on the inhibitory concentration(IC_(50)) obtained from the cell viability assay,graded concentrations of extracts,fractions or isolated compound were assessed(10,20,50,100,200 μg/mL) for its hepatoprotective potential against CCl_4-induced hepatotoxicity by monitoring activity levels of serum glutamatic pyruvatic transaminase(SGPT) and serum glutamic oxaloacetic transaminase(SGOT).Results:Results indicated that the methanol extract of F.limonia was non-toxic and hepatoprotective in nature as compared with the petroleum ether extract.The acetone fraction of methanolic extract also showed similar properties but the subsequent two fractions were cytotoxic.However,the pure compound isolated from the penultimate fraction of methanolic extract was non-toxic and hepatoprotective in nature.Biochemical investigations(SCOT,SCPT) further corroborated these cytological observations.Conclusions:It can be concluded from this study that F.limonia methanol extract,some fractions and pure isolated compound herein exhibit hepatoprotective activity.However,cytotoxicity recorded in the penultimate fraction and investigation of structural details of pure compound warrants further study.
文摘The distribution of temperature and then the distribution of residual stress and distortion in the stiffened aluminum alloy Al6061-T6 plates under the metal inert gas(MIG)welding process were investigated by three dimensional thermo-mechanical coupled finite element model using Ansys software.The properties of materials were considered temperature-dependent and the filler metal was added to the workpiece by the element birth and death technique.In three modes of current,two different speeds and two various sequences,the distribution of residual stress and distortion were calculated and analyzed.The results showed that increase in welding speed decreased the vertical deflection in the plate,transverse shrinkage and angular distortion of plate and the lateral deflection of stiffener,but increased the maximum longitudinal tensile stress in the plate and stiffener.Furthermore,increase in current increased the residual stress and deformation in the plate and stiffener,and the change in the welding sequence changed the distribution of the distortion in the plate and the stiffener without significant change in the distribution of the longitudinal residual stress.
基金financially supported by the Special Fund for Agro-scientific Research in the Public Interest of China(Grant No.201503119)the National Key Technologies R&D Program of China(Grant No.2015BAD06B04)the Scholarship Award for Excellent Doctoral Student granted by Yunnan Province
文摘Intercropping, as an overyielding system, can decrease soil erosion on sloping land through the presence of dense canopy covers. However, the structure mechanism in canopy is still unclear. We conducted a two-year field experiment on runoff plots, exploring whether the interaction between vegetation layers reduce soil erosion in maize and potato intercropping systems. The maize, potato, and weed layers in the intercropping system were removed by a single layer, two layers and three layers, respectively(total of 8 treatments including all layers removed as the control). Then, throughfall, runoff and sediment were measured at the plot and row scale on a weekly basis. Based on the difference between each treatment and the control, we calculated and found a relative reduction of runoff and sediment by any combination of the two vegetation layers greater than the sum of each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 15.65% and 46.73%, respectively. Sediment loss decreased by 33.96% and 42.77%, respectively. Moreover, runoffand sediment reduced by the combination of all vegetation layers(no layers removed) was also larger than the sum of that by each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 7.32% and 3.48%, respectively. So, there were synergistic effects among multi-level(two or three layers) vegetation layers in terms of decreasing soil erosion on sloping land. Maize redistributes more throughfall at the maize intra-specific row and the maize and potato inter-specific, which is favorable for the synergistic effect of reducing soil erosion. This finding shows an important mechanism of maize and potato intercropping for soil and water conservation, and may promote the application of diverse cropping systems for sustainable agriculture in mountainous areas.
文摘Eringen's nonlocal elasticity theory is extensively employed for the analysis of nanostructures because it is able to capture nanoscale effects.Previous studies have revealed that using the differential form of the strain-driven version of this theory leads to paradoxical results in some cases,such as bending analysis of cantilevers,and recourse must be made to the integral version.In this article,a novel numerical approach is developed for the bending analysis of Euler-Bernoulli nanobeams in the context of strain-and stress-driven integral nonlocal models.This numerical approach is proposed for the direct solution to bypass the difficulties related to converting the integral governing equation into a differential equation.First,the governing equation is derived based on both strain-driven and stress-driven nonlocal models by means of the minimum total potential energy.Also,in each case,the governing equation is obtained in both strong and weak forms.To solve numerically the derived equations,matrix differential and integral operators are constructed based upon the finite difference technique and trapezoidal integration rule.It is shown that the proposed numerical approach can be efficiently applied to the strain-driven nonlocal model with the aim of resolving the mentioned paradoxes.Also,it is able to solve the problem based on the strain-driven model without inconsistencies of the application of this model that are reported in the literature.
文摘Rapid and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and ultra performance liquid chromatography (RP-UPLC) method with UV detection has been developed and validated for quantification of parathyroid hormone (PTH) in presence of meta-cresol as a stabilizer in a pharmaceutical formulation.Chromatography was performed with mobile phase containing 0.1% Trifluoroacetic acid (TFA) in MilliQ water and 0.1% TFA in acetonitrile with gradient program and flow rate at 0.3 mL/min for HPLC and 0.4 mL/min for UPLC.Quantification was accomplished with internal reference standard (qualified against innovator product and National Institute for Biological Standards and Control (NIBSC) standard).The methods were validated for linearity (correlation coefficient 0.99),range,accuracy,precision and robustness.Robustness was confirmed by considering three factors;mobile phase composition,column temperature and flow rate/age of mobile phase.Intermediate precision was confirmed on different equipments,different columns and on different days.The relative standard deviation (RSD) (<2% for RP-HPLC and <1% for UPLC,n=30) indicated a good precision.Retention time was found about 17 min and 2 min by HPLC and UPLC methods,respectively.Both methods are simple,highly sensitive,precise and accurate and have the potential of being useful for routine quality control.
文摘This study focuses on the development of a farm of tidal turbines in the Khuran Channel.The important factors include the location of turbines and their hydrodynamic effects on the environment.A three-dimensional circulation model for the Persian Gulf is employed for the comprehensive evaluation of the tidal energy potential throughout the study area.The model is validated by using in situ observations of water level and current data.The appropriate potential points for extracting the tidal energy were identified in the Persian Gulf using the model results.The Khuran Channel,located in the north of Qeshm Island,was found to be the best place to extract tidal energy inside the Persian Gulf.By adding the term of momentum losses to the governing equations,the feedback of extracting energy on the hydrodynamic around Qeshm Island was studied.The simulation results show that the average daily power production of a tidal farm with 99 turbines for one month is approximately 1.3 MW.This tidal farm also has a significant impact on the water level inside the Khuran Channel,especially near the tidal farm where these fluctuations exceed 4 cm.The change in the current speed caused by wake reaches 0.4 m/s.Wake effects were active up to 7 km downstream of the turbines.The current velocity was also estimated to be 1.6 m/s and 2.1 m/s during the spring and ebb tides within the channel,respectively.
文摘The size-dependent nonlinear buckling and postbuckling characteristics of circular cylindrical nanoshells subjected to the axial compressive load are investigated with an analytical approach. The surface energy effects are taken into account according to the surface elasticity theory of Gurtin and Murdoch. The developed geometrically nonlinear shell model is based on the classical Donnell shell theory and the von Karman＇s hypothesis. With the numerical results, the effect of the surface stress on the nonlinear buckling and postbuckling behaviors of nanoshells made of Si and Al is studied. Moreover, the influence of the surface residual tension and the radius-to-thickness ratio is illustrated. The results indicate that the surface stress has an important effect on prebuckling and postbuekling characteristics of nanoshells with small sizes.
文摘Risk assessment and uncertainty approximation are two major and important parameters that need to be adopted for the development of pharmaceutical process to ensure reliable results.Additionally,there is a need to switch from the traditional method validation checklist to provide a high level of assurance of method reliability to measure quality attribute of a drug product.In the present work,evaluation of risk profile,combined standard uncertainty and expanded uncertainty in the analysis of acyclovir were studied.Uncertainty was calculated using cause-effect approach,and to make it more accurately applicable a method was validated in our laboratory as per the ICH guidelines.While assessing the results of validation,the calibration model was justified by the lack of fit and Levene＇s test.Risk profile represents the future applications of this method.In uncertainty the major contribution is due to sample concentration and mass.This work demonstrates the application of theoretical concepts of calibration model tests,relative bias,risk profile and uncertainty in routine methods used for analysis in pharmaceutical field.
文摘This study investigated the effect of Zn foil layers on the microstructure and corrosion characteristics of friction stir welded aluminum alloy 5754.Samples of various joints were prepared by applying different rotational and welding speeds,and their microstructures were evaluated via a metallographic technique and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy elemental analysis.The anticorrosion behavior of joints in the absence and presence of a Zn interlayer was studied by cyclic potentiodynamic polarization test in 3.5 wt% Na Cl aqueous solution,and sound welds were obtained in the presence of the Zn interlayer foil.The results revealed that the joint made at a rotational speed of 800 r/min and traveling speed of 15 mm/min achieved a chemical composition identical to that of aluminum alloy 7 xxx series,and as such,it showed the best resistance to corrosion.
基金Supported by All India Couneil for Technical Education(AICTE)(Grant No.1-10/RID/NDF-PG/(28)/2007-08)
文摘Objective:To assess the protective effects of lycopene on electrocardiographic,hemodynamic, biochemical and apoptotic changes in isoproterenol induced myocardial infarction.Methods: Myocardial infarction was induced in rats by subcutaneous injection of isoproterenol(200 mg/kg) for two consecutive days at an interval of 24 h.Rats were treated with lycopene(10 mg/kg/day, p.o.) for a period of 30 days and isoproterenol(ISO) was injected on the 29th and 30th day.At the end of experiment i.e.on the 31st day electrocardiographic,hemodynamic,biochemical and apoptotic changes were monitored from control and experimental groups.Results:ISO injected ruts showed a significant alteration in electrocardiograph pattern and hemodynamic changes(i.e. systolic,diastolic and mean arterial pressure).It also showed significant increase in C-reactive protein,myeloperoxidase,nitrite levels and Caspase-3 protease activity.In addition,it also exhibited alteration in the levels of electrolytes(Na^+,K^+ and Ca^(2+),vitamin E,uric acid and serum protein.Cel electrophoresis of ISO injected rats showed increase in DNA fragmentation.Triphenyl tetrazolium chloride staining of the heart section shows increase area of infarction in ISO injected rats.Pre-co-treatment with lycopene significantly prevented the ISO induced ullerution in ECC, haemodynamic,biochemical and apoptotic changes.Conclusions:The present result shows that treatment of lycopene in ISO injected rats significantly attenuates induced myocardial infarction.
文摘Dry powder inhaler Liposomes were prepared to investigate the effectiveness of pulmonary delivery of Colchicine and Budesonide for Idiopathic Pulmonary fibrosis. Budesonide(BUD) and Colchicine(COL) liposomes were prepared by thin layer film hydration method(TFH) using 1,2-Dipalmitoyl-sn-glycero-3-phosphoglycerol sodium(DPPG), Hydrogenated Soyaphosphotidylcholine(HSPC), Soyaphosphatidylcholine(SPC), cholesterol(CHOL) and drug in different weight ratios. The optimum lipid composition for BUD(74.22 ± 0.97%) was DPPG:HSPC: CHOL(4:5:1) and for COL(50.94 ± 2.04%) was DPPG: SPC: CHOL(3:6:1). These compositions retained drug for a longer period of time so selected for further study. Liposomes were found to be spherical in shape with mean size below 100 nm. Liposomes lyophilized using Mannitol as carrier and cryoprotectant showed high entrapment efficiency(97.89-98.6%). The powder was dispersed through an Andersen cascade impactor to evaluate the performance of the aerosolized powder. It was found that prepared liposomal dry powder inhaler(DPIs) sustained the drug release up to 24 hours. Optimized Budesonide DPI Formulation B2(86.53 ± 1.9%), Colchicine DPI Formulation C2(90.54 ± 2.3 %) and BUD and COL DPI Combination M2(89.91 ± 1.8%, 91.23 ± 1.9%). Histopathological results, measurements of lung hydroxyproline content, Myeloperoxidase activity indicated that liposomal drypowder inhaler administration attenuates lung fibrosis induced by bleomycin. Long term stability studies indicated that lyophilised BUD and COL liposomes were stable for 6 months at(25 °C± 2 °C, 60% ± 5% RH) and refrigerated conditions(2-8 °C). These results supported that combination of budesonide and colchicine liposomal dry powder inhaler pulmonary drug delivery for treatment of idiopathic Pulmonary Fibrosis exhibits prolonged drug retention at targeted site and reduces the systemic exposure.
基金Department of Pharmacology,KBIPER,Gandhinagar,Gujarat,India for providing the funds the University Grants,The MS University of Baroda for providing research fellowship
文摘Objective:To investigate the protective effects of hydroalcoholic and its fractions from roots of Hemidesmus indicus on arthritis in in vitro models of rodents.Methods:Preliminary phytochemical analysis and thin-layer chromoatography were performed to analyze constituents of hydroalcoholic extract and its three fraction namely ethyl acetate fraction,chloroform fraction and residual fraction of mot of Hemidesmus indicus.Arthritis rats models were established by Complete Freund’s Adjuvant.The parameters including paw edema,body weight,arthritic index,erythrocyte sedimentation rate,serum rheumatoid factor,serum C-reactive protein,serum nitrite level,and histopathology of synovial joints were observed.Methotrexate was taken as positive control.Results:Rats treated with hydroalcoholic extract(450 mg/kg,p.o.),ethyl acetate (75 mg/kg,p.o.),chloroform(60 mg/kg,p.o) and residual fractions(270 mg/kg,p.o.),showed significant decrease in physical and biochemical parameters compared with arthritic model rats. Hydroalcoholic extract and its ethyl acetate fraction of Hemidesmus indicus showed significantly higher anti-arthritic activity than chloroform and residual fraction.Histopathological analysis demonstrated that both of hydroalcoholic extract and its ethyl acetate fraction had comparable anti-arthritic activity with methotrexates.Conclusions:The present study suggests that Hemidesmus indicus has protective activity against arthritis and the activity might be attributed to presence of terpenoid in hydroalcoholic extract,as well as in ethyl acetate fraction.
文摘A novel size-dependent model is developed herein to study the bending behavior of beam-type micro/nano-structures considering combined effects of nonlocality and micro-rotational degrees of freedom. To accomplish this aim, the micropolar theory is combined with the nonlocal elasticity. To consider the nonlocality, both integral (original) and differential formulations of Eringen’s nonlocal theory are considered. The beams are considered to be Timoshenko-type, and the governing equations are derived in the variational form through Hamilton’s principle. The relations are written in an appropriate matrix-vector representation that can be readily utilized in numerical approaches. A finite element (FE) approach is also proposed for the solution procedure. Parametric studies are conducted to show the simultaneous nonlocal and micropolar effects on the bending response of small-scale beams under different boundary conditions.
文摘An analytical approach is proposed to study the postbuckling of circular cylindrical shells subject to axial compression and lateral pressure made of functionally graded graphene platelet-reinforced polymer composite (FG-GPL-RPC). The governing equations are obtained in the context of the classical Donnell shell theory by the von K′arm′an nonlinear relations. Then, based on the Ritz energy method, an analytical solution approach is used to trace the nonlinear postbuckling path of the shell. The effects of several parameters such as the weight fraction of the graphene platelet (GPL), the geometrical properties, and distribution patterns of the GPL on the postbuckling characteristics of the FG-GPL-RPC shell are analyzed.
文摘This paper describes a sensitive spectrophotometric method developed for determination of Ketoconazole (KC) in tablets based on amplification reactions. Ketoconazole was oxidized with periodate, resulting in formation of KC2t and iodate ions. After masking the excess periodate with molybdate, the iodate was treated with iodide to release iodine. The liberated iodine was transformed to ICl2 species and extracted as ion-pair with rhodamine 6G into toluene for spectrophotometric measurement at 535 nm. A linear calibration graph was obtained between 0.2136 mg/mL and 1.7088 mg/mL of Ketoconazole with a molar absorptivity of 5 105 mol L 1 cm 1. The procedure was successfully applied for the determination of ketoconazole in tablet formulation.
文摘The(1+2)-dimensional chiral nonlinear Schr?dinger equation(2D-CNLSE)as a nonlinear evolution equation is considered and studied in a detailed manner.To this end,a complex transform is firstly adopted to arrive at the real and imaginary parts of the model,and then,the modified Jacobi elliptic expansion method is formally utilized to derive soliton and other solutions of the 2D-CNLSE.The exact solutions presented in this paper can be classified as topological and nontopological solitons as well as Jacobi elliptic function solutions.
文摘In this paper, thermoluminescence （TL） properties of rare earth Tb^3＋-doped α-Sr2P2O7 were examined after β-irradiation and photoluminescence （PL） properties of samples were examined for proper excitation. All the samples were synthesized by high-temperature combustion method. The X-ray diffraction （XRD） and Fourier transform infrared （FTIR） spectroscopy characterization confirms the formation of pure α-phase with crystallized in orthorhombic structure of samples. The PL emission spectra of all samples exhibit characteristic green emission peaks of Tb^3＋ where the peak at 545 nm has the highest emission intensity for Tb^3＋ con- centration of 5.0 mol%. The TL glow curves of β-irradiated Tb^3＋-doped α-Sr2P2O7 phosphors were recorded at different heating rates of 2, 4, and 6 K.s^-1. TL curves of all sample exhibit combination of two peaks： peak at 420 K shifts toward higher 525 K remains unaffected temperature, while peak at with the increase in Tb^3＋ concentration as well as fading effect. The activation energy and kinetic parameters of the samples were evaluated using thermoluminescence peak shape method.
基金supported by the National Natural Science Foundation of China (Grant Nos.11975172 and 12261131495)。
文摘To study controlled evolution of nonautonomous matter-wave breathers and rogue waves in spinor Bose–Einstein condensates with spatiotemporal modulation,we focus on a system of three coupled Gross–Pitaevskii equations with spacetime-dependent external potentials and temporally modulated gain-loss distributions.With different external potentials and gain-loss distributions,various solutions for controlled nonautonomous matterwave breathers and rogue waves are derived by the Darboux transformation method,such as breathers and rogue waves on arched and constant backgrounds which have the periodic and parabolic trajectories.Effects of the gain-loss distribution and linear potential on the breathers and rogue waves are studied.Nonautonomous two-breathers on the arched and constant backgrounds are also derived.
文摘In this study,we analyze three portfolio selection strategies for loss-averse investors:semi-variance,conditional value-at-risk,and a combination of both risk measures.Moreover,we propose a novel version of the non-dominated sorting genetic algorithm II and of the strength Pareto evolutionary algorithm 2 to tackle this optimization problem.The effectiveness of these algorithms is compared with two alternatives from the literature from five publicly available datasets.The computational results indicate that the proposed algorithms in this study outperform the others for all the examined performance metrics.Moreover,they are able to approximate the Pareto front even in cases in which all the other approaches fail.
